Question

Consider a uniport system where a carrier protein transports an uncharged substance across a cell membrane. What is the function of the carrier protein in this system?

1) Facilitate passive diffusion of the substance
2) Facilitate active transport of the substance
3) Facilitate osmosis of the substance
4) Facilitate endocytosis of the substance

Answer 1

A carrier protein in a uniport system enables the passive diffusion of a specific substance across a cell membrane by changing its shape to move the substance without the use of energy.

Step-by-step explanation:

The function of the carrier protein in a uniport system is to facilitate passive diffusion of a substance across a cell membrane. A uniporter is a type of transporter that carries one specific ion or molecule. In the process known as facilitated diffusion, the substance binds to the carrier protein, the protein changes shape and moves the substance across the membrane without the use of energy (ATP). Carrier proteins are specific for the substance they transport, and their action results in the substance moving down its concentration gradient, from a region of higher concentration to one of lower concentration.